A randomized, controlled, prospective trial to evaluate the haemostatic effect of Lyostypt versus Surgicel in arterial bypass anastomosis: "COBBANA" trial

<p>Abstract</p> <p>Background</p> <p>The development of suture hole bleeding at peripheral arterial bypass anastomoses using PTFE graft prostheses is a common problem in peripheral vascular surgery. Traditionally the problem is managed by compression with surgical swabs and reversal heparin or by using several haemostatic device (e.g. different forms of collagen, oxidized cellulose, gelatine sponge, ethylcyanoacrylate glue or fibrin) with various success. Preclinical data suggest that the haemostatic effect of collagen is stronger than that of oxidized cellulose, but no direct clinical comparison of their hemostatic performance has been published so far.</p> <p>Design</p> <p>This randomized, controlled, prospective trial evaluates the haemostatic effect of Lyostypt versus Surgicel in arterial bypass anastomosis. 28 patients undergoing an elective peripheral vascular reconstruction due to peripheral vascular disease will be included. Suture hole bleeding occurring at the arterial bypass anastomosis using a PTFE prostheses will be stopped by the application of Lyostypt and/or Surgicel. The proximal anastomoses will be randomized intraoperatively. The patients will be allocated into 4 different treatment groups. Group1 Lyostypt distal/Surgicel proximal; Group 2: Lyostypt proximal/Surgicel distal; Group 3: Surgicel distal and proximal; Group 4: Lyostypt distal and proximal. Primary endpoint of the study is time to haemostasis. Secondary endpoints are the number of intraoperatively used haemostatic devices, postoperative mortality within 30 days as well as the intraoperative efficacy rating of the two devices evaluated by the surgeon. As a safety secondary parameter, the local and general complication occurring till 30 ± 10 days postoperatively will also be analysed. After hospital discharge the investigator will examine the enrolled patients again at 30 days after surgery.</p> <p>Discussion</p> <p>The COBBANA trial aims to assess, whether the haemostatic effect of Lyostypt is superior to Surgicel in suture hole bleedings of arterial bypass anastomoses.</p> <p>Trial registration</p> <p>NCT00837954</p

Optimised Vascular Network for Skin Tissue Engineering by Additive Manufacturing

Artificial vascular vessels, including arteries, veins and capillaries, are being printed using additive manufacturing technologies. Additive manufacturing allows the manufacture of artificial blood vessels and their networks of any sophisticated geometry. This chapter demonstrates the essential and efficient methods to design and fabricate optimal vascular network for tissue engineering structures following the physiological conditions. Comprehensive physiological requirements in both micro- and macro-scales were considered in developing the optimisation design for artificial vascular networks. The optimised vascular vessel offers three advantages: (1) it provides the maximum nutrient supply; (2) it minimises the recirculation areas and (3) it allows the wall shear stress on the vessel in a healthy range. Two main design technologies are used in the chapter to achieve the design. They are computer graphics and computational fluid dynamics. The optimised design was then manufactured by the stereolithography process using materials that are biocompatible, elastic and surface bio-coatable. The stereolithography manufactured vascular vessels were embedded in the hydrogel seeded with cells afterward. The results of in vitro studies show that the optimised vascular network has the lowest cell death rate compared with a pure hydrogel scaffold and a hydrogel scaffold embedded within a single tube in day seven. The combination of the optimised micro- and macro-design, the material selection and the manufacturing methods completes a general guide for future artificial vascular vessel network developments